Process for the production of highmoleuclar compounds containing epoxide groups



Unitcd States Patent Ofifice 3,12%,547 Patented Feb. 4, 1964 PRGCESd ltiR THfiPRUDUQTlON OF HIGH- MULECULAR CGIi WGUNDS tIQNTAG EPOXEDE GRGUPSGerhard Dieclreimann, Dusseldorf-Holthausen, Germany, assignor toDehydag, Deutsche Hydrierwerke G.m.b.H., Dusseldorf, Germany, acorporation of Germany No Drawing. Filed June 25, 1958, Ser. No. 744,350Claims priority, application Germany June 29, 1957 1 Claim. (Cl.26tl-348.5)

This invention relates to an improved process of producing epoxidizedhigh-molecular weight organic compounds and to the compounds soprepared.

I have found that high-molecular weight organic compounds containingepoxide groups can be obtained by reacting high-molecular weightolefinicallymnsaturated compounds containing lipophilic radicals withdior polycarboxylic acids in the presence of activators capable offorming mixed anhydrides, treating the mixture with hydrogen peroxideand isolating the epoxide compounds formed thereby. The total amount ofdior polycarboxylic acid and acid activator should, as a rule, be nogreater than 0.5 mol per double bonds of the starting materialcalculated on a molar basis. The reaction tem peratures to be appliedlie between and 100 C., preferably between 40 and 60 C.

Examples of suitable olefinically-unsaturated highmolecular weightstarting components are the following: aliphatic high-molecular weightolefinic hydrocarbons, derivatives of olefinically-unsaturatedhigh-molecular weight hydrocarbon alcohols, such as the esters ofalcohols obtained by reduction of natural-occurring vegetable or animalolefinically-unsa-turated fatty acids under preservation of the doublebond hereinafter sometimes referred to as olefinically-unsaturated fattyalcohols, or esters of olefinically-unsaturated alcohols which areobtained by splitting natural Wax esters, such as esters ofolefinicallyunsaturated fatty alcohols having from 14 to 18 carbonatoms, especially of oleyl alcohol and other monoorpoly-olefinically-unsaturated alcohols formed with any desiredlow-molecular weight or high-molecular weight carboxylic acids. Alsosuitable are the corresponding ethers of the above-mentioned unsaturatedalcohols formed preferably with low-molecular weight alcohols.

Furthermore, derivatives of olefinically-unsaturated high-molecularweight fatty acids, such as their esters, amides or nitriles may be usedas starting materials. Especially suitable are the natural-occurringglycerides, the fatty acid moiety of which may be mono-unsaturated orpoly-unsaturated, such as the semi-drying oils, primarily soybean oil,cottonseed oil and linseed oil. Similarly suitable are olive oil, neatsfoot oil, sperm oil and other aquatic animal oils. Examples of otheresterifying components for the unsaturated fatty acids are the followingalcohols: ethyl, isopropyl, n-butyl, secondary butyl, tertiary butyl,tertiary amyl, n-octyl, 2-ethylhexyl, dodecyl, octadecyl, ootadecenyl,cyclohexyl, methylcyclohexyl, naphthenyl, benzyl alcohols, and the like,polyvalent alcohols, such as ethylene glycol, 1,2-propylene glycol, 2-ethylhexanediol 1,3,butanediol 1,2,butanediol1,3,butanediol-1,4,dodecanediol-1,12, glycol, polyalkylene glycols, suchas diethylene glycol, glycerin, pentaerythrite, and the like. Similarly,esters formed by the unsaturated fatty acids and alcohol mixtures may beused as starting materials as well as mixed esters formed by polyvalentalcohols and varying unsaturated fatty acids; for example, the mixedesters formed by ethylene glycol with oleic acid and linseed oil fattyacid. Finally, the esters in which the alcohol moiety as well. as theacid moiety possesses a high-molecular weight aliphatic monounsaturatedor poly-unsaturated hydrocarbon radical may also be used. In addition tothe esters, amides of olefinicallyunsaturated fatty acids may be used asstating materials, such as the amidation products of unsaturated fattyacids or fatty acid mixtures produced with ammonia, d-imethylamine,dodecylamine, oleylamine, ethylenediamine, cyclohexylamine,benzylzuniue, etc. Examples of nitriles of unsaturated fatty acids whichmay be used are tetradecenyl nitrile, hexadecenyl nitrile or alsomixtures of alkenyl nitriles having from 14 to 18 carbon atoms in themolecule.

In accordance with the present invention, the abovementioned startingmaterials are treated with Ian epoxidizing mixture containing diorpolycarboxylic acids. Dior polycarboxylic acids which are suitable forthis purpose are, for example, succinic acid, adipic acid, maleic acidor its halogen-substitution products, fuma-ric acid, citric acid,acetonedicarboxylic acid, sebacic acid, phthalic acids,benzenepolycarboxylic acids or their halogenation products; polyacrylicacids or other polycondensation products containing several carboxylgroups, base-exchange resins containing carboxyl groups, and so forth.It is also possible to use mixtures of dior polycarboxylic acids for theepoxidation. Furthermore, polybasic carboxylic acids or their mixtureswhich have been obtained by oxidation cleavage of saturated orunsaturated fatty acids, or their esters, may also be used.

Examples of activators accelerating peracid formation which are capableof forming mixed anhydrides with the above-mentioned dior polycarboxylicacids are organic or inorganic acids or acid halides, such as mineralacids, including phosphoric acid, nitric acid and sulfuric acid,

erchloric acid, borontrifluoride or boron trilluoride-Water adducts,acid phosphoric acid esters, p-toluenesulfonic acid, high-molecularweight resins containing sulfonic acid groups, and the like. Some ofthese activators are known under the name of Lewis acids. Theseactivators are capable of facilitating or accelerating the peracidformation in that they combine with the dior polycarboxylic [acids in anintermediate step to form energy-rich mixed anhydrides.

The 'epoxidation takes place by virtue of the fact that the diorpolycarboxylic acids are rendered capable of reacting with the hydrogenperoxide and forming organic peracids in the presence of thehigh-molecular Weight olefinically-u-nsaturated compounds, due to theinfluence of the activators, and that the peracids cause the transfer ofthe active oxygen to the double bond of the highmolecular weightolefinically-unsaturated compounds.

The quantitative ratios of the reaction components which are usedaccording to the present invention depend primarily upon the number ofdouble bonds present in the starting material which are to betransformed into epoxide groups.

The concentration of active oxygenathat is, the content of hydrogenperoxide-should lie between 1.1 and 2 mols per molar equivalent ofdouble bonds. In general, the required maximum amount of diorpolycarboxylic acids and activator should not exceed a total of 0.5 molper molar equivalent of double bonds. However, in those cases where abase-exchange resin containingcarboxyl groups is used as anoxygen-transfer agent larger quantities can be used. For reasons ofeconomy and for the purpose of suppressing side-reactions, it isadvantageous to maintain the amount of dior polycarboxylic acids as lowas possible. When excessive quantities of dior polycarboxylic acids areused, the reaction rate and the reaction temperature may be increased tosuch an extent that the epoxide groups are cleaved and dihy droxy andacyloxy derivatives are formed with a corresponding decrease in thevalue of the epoxide compounds ried out by first admixing the startingmaterial to be epoxidized with the dior polycarboxylic acids and theacid activators in the reaction vessel and then raising the mixture totemperatures of preferably 40 to 60 C. Thereafter the calculated amountof an at least 30%, but preferably 50 to 60%, aqueous hydrogen peroxidesolution is added slowly and gradually over a period of several hours,accompanied by vigorous stirring, while maintaining the reactiontemperature at the indicated value by cooling, if necessary. After theaddition of hydrogen peroxide has been completed, it is in many casesadvantageous to increase the temperature of the reaction mixture bydiscontinuing the cooling and supplying additional heat, if necessary,in order to bring the reaction to completion.

The process according to my invention has a number of advantages overother known epoxidizing processes. By continuing the addition ofhydrogen peroxide over a period of several hours, the oxidizing agent isalways present in such dilute form that the limits of explosiveconcentration of the organic peracids which form as inter mediateproducts are not reached. Moreover, the organic peracids formed fromdior polycarboxylic acids are not nearly as explosive as the peraceticacid or performic acid formed during the known epoxidation processes. Incomparison with known processes in which the total required amount ofhydrogen peroxide is added to the reaction mixture at the beginning, theprocess according to my invention makes it easier to control theepoxidation process by controlling the course of the exothermicreaction. Because of the delayed course of reaction, the danger offormation of undesirable dihydroxy or acyloxy compounds by cleavage ofthe epoxide ring is also reduced. In those cases where synthetic resinscontaining carboxyl groups are used, as the required polycarboxylic acidcomponent, a further advantage is derived in that they do not cause acleavage of the epoxide groups formed during the reaction, even whenpresent in amounts above 0.5 mol per molar equivalent of double bonds.Moreover, the reaction product obtained in accordance with the presentinvention is much easier to work up after completion of the reactionthan when formic acid or acetic acid is used, because the diorpolycarboxylic acids used as oxygen-transfer agents in accordance withthe invention are present in solid form after cooling of the reactionmixture, and may thus be separated from the epoxide compounds byfiltration and may be reused without further regeneration treatment.

The high-molecular weight epoxide compounds obtained in accordance withthe above method are of manifold technical interest. For example,because of their excellent compatibility and resistance to migration,they are useful as auxiliary agents in the production of synthetics,e.g. in the role of softeners and stabilizers for polyvinyl chloride andits mixed polymerizates. Furthermore, they may be used as lubricants andlubricating oil additives or textile oils.

The following examples will further illustrate the present invention andenable others skilled in the art to understand it more completely. Itwill be understood, however, that the invention is not limited to theseparticular examples.

Example 1 Into a stirring vessel made of VA-steel and provided with acoil heater and a cooling jacket, 750 parts by weight of a soybean oil(acid number 0.2; esterification number 188; hydroxyl number 2; iodinenumber 122), 100 parts by weight of technical-grade succinic acid andparts by weight of 70-80% sulfuric acid were placed. The contents of thevessel were then heated to a temperature of 40-45 C. Thereafter, 300parts by weight of a hydrogen peroxide solution containing 50% by weighthydrogen peroxide were added to the mixture during the course of 3-4hours, accompanied by stirring, while maintaining the temperature at40-45 C. by cooling the vessel. After completion of the hydrogenperoxide addition, the temperature of the contents was allowed to riseto 50-60 C. by reducing the cooling. At this temperature the reactionproduct was stirred for 10-12 hours and was then washed with water untilneutral. In order to remove small residual amounts of acid components,the reaction product was refined with dilute alkali and finally washeduntil neutral.

By heating the resultant product to a temperature of 70-90 C. underreduced pressure, a dry epoxidized soybean oil having an epoxide-oxygencontent of 5.3% (iodine number 31.2; acid number 0) was obtained.

Example II The procedure described in Example I was repeated except thatin place of succinic acid 50 parts by weight of adipic acid and 50 partsby weight of concentrated phosphoric acid were used in the reaction.After a reaction period of 15 hours, an epoxidized soybean oil havanepoxide-oxygen content of 4.3% (acid number 0; iodine number 50.2) wasobtained.

Example III A synthetic-ion-exchange resin containing carboxyl groups(Levatit CNO) was allowed to swell in dilute phosphoric acid and after 2to 3 hours standing was squeezed free from excess acid. parts by weightof the resin thus pretreated were suspended in 50 parts by Weight ofconcentrated phosphoric acid. The resultant suspension was stirred for afew hours and then again squeezed to remove excess liquid components.750 parts by weight of a thoroughly deacidified soybean oil (acid number0.2; esterification number 188.5; hydroxyl number 2.9; iodine number129) were added to this resin, and then 300 parts by weight of a 60% byvolume hydrogen peroxide solution was added thereto at a temperature ofabout 40-45 C., accompanied by stirring. The hydrogen peroxide was addedover a period of 3 hours. Thereafter, the temperature was allowed torise to about 50-60 C. and the mixture was stirred for 10-12 hours.Subsequently, the solid components of the reaction mixture wereseparated from the raw epoxide with the aid of a filter. The raw epoxidewas refined in accordance with known methods, washed and dried. Aproduct having an epoxide-oxygen content of 3.24% (acid number 0; iodinenumber 67.7) was obtained.

Example IV 1000 parts by wei ht of a cottonseed oil fattyacidmethylcyclohexyl ester (produced from the liquid components ofcottonseed oil fatty acids and methylcyclo- 'hexanol; saponificationnumber 147; iodine number 97; acid number 0.17; hydroxyl number 1.4)were admixed with 131.5 parts by weight of succinic acid and 13.2 partsby weight of 70-80% sulfuric acid, and the mixture was heated to atemperature of 40-45 C. Thereafter, 400 parts by weight of a hydrogenperoxide solution containing 60% by volume hydrogen peroxide were addedto the mixture over a period of 4 hours, while carefully maintaining thetemperature of 45 C. Subsequently, the temperature of the reactionmixture was allowed to increase to 50-60 C. and the mixture was stirredfor 12-14 hours. The contents of the reaction vessel were allowed tocool and were then filtered to remove the succinic acid which hadprecipitated mostly in crystalline form. About 75-80% of the originalamount of catalyst was thus recovered. The succinic acid can be reusedin a subsequent run. The reaction product was then deacidified in arefining container, washed and then freed from water under reducedpressure. The epoxide thus obtained had an epoxide-oxygen content of4.2% and an iodine number of 12.4.

Example V By proceeding in accordance with the procedure described inExample 1, but using 100 parts by weight of citric acid instead ofsuccinic acid, a product having an epoxide-oxygen content of 3.0% (acidnumber 0; iodine number 76) was obtained.

Example VI 200 parts by weight of -a soybean fatty acid-butyl ester(acid number 0; saponification number 165; hydroxyl number 2; iodinenumber 110) were epoxidized in accordance with the procedure describedin Example I in the presence of 60 parts by weight of succinic acid and12 parts by Weight of 70-80% sulfuric acid with 360 parts by weight of ahydrogen peroxide solution c0nt aining 60% by volume hydrogen peroxide.After working up the reaction mixture, an ester-epoxide with anepoxideoxygen content of 4.10% and an iodine number of 15.0 wasobtained. 1

Example VII A synthetic ion-exchange resin containing sulfonic acidgroups (Amberlite IR. 120) is preliminarily treated with diluted mineralacid, washed and dried.

To a mixture of 68 parts by weight of this resin,

140 parts by weight adapic acid and 2500 parts by weight syntheticsoybean oil fatty acid glycerin ester (acid number 0.3, iodine number121, hydroxyl number 3.0)

obtained by reesterification of the fluid portions of soybean oil fattyacid and glycerin, are added, while stirring during 4-5 hours at atemperature not exceeding 65 C. in a steel vessel, 1300 parts by weightof 50% by weight hydrogen peroxide. During the epoxidation process thetemperature is kept at 60-75 C. After a reaction time of about 20 28hours the mixture is cooled down and the solid portions of the mixtureare separated from the fluid portions in a usual manner. The thusobtained synthetic ion-exchange resin is Washed and dried and may bereused in the next charge. The fluid raw product is freed from the acidpontions by washing with diluted soda lye, washed with water untilneutral and dried.

The soybean oil epoxide is refined by treating with fullers earth andactive carbon and shows after that an epoxide-oxygen content of 6.06%and an iodine number 1.6.

Instead of the above described synthetic ion-exchange resin one may usein the like manner other high-molecular weight resins containing freeacid especially sulfonic acid 6 groups as they are described e.g. inPlaste und Kautschuk, 1955', pages 74-78.

In like manner other high-molecular weight fatty acid derivatives suchas the fatty acid amides and fatty acid nitriles and the high-molecularweight fatty alcohols can also be epoxidized by my invention.

While I have disclosed various specific embodiments of my invention, itwill be apparent to persons skilled in the art that the presentinvention is not limited to these spe cific embodiments and that variouschanges and modifications may be made without departing from the spiritof the invention or the scope of the appended claim.

I claim:

A process for the introduction of 1,2-epoxy groups into esters ofhigh-molecular weight, olefinically-unsaturated fatty acids containingfrom 12 to 26 carbon atoms comprising (A) mixing said fatty acid esterwith a synthetic ion-exchange resin containing free carboxyl groups andan acid activator capable of forming a mixed anhydride with said freecarboxyl groups and accelerating per acid formation selected from thegroup consisting of mineral acids, organic sulfonic acids and syntheticresins containing sulfonic acid groups which serve as proton donors,said ion-exchange resin containing free carboxyl groups and said acidactivator being added in an amount in combination of less than 0.5 molefor each double bond in each mole of said fatty acid, (1B) adding slowlyover a period of several hours from 1.1 to 2.0 moles for each doublebond in each mole of said fatty acid ester of hydrogen peroxide in asolution containing at least hydrogen penoxide while stirring vigorouslyand maintaining the reaction temperature between 40 C. and C., (C)allowing the reaction to proceed to completion and (D) isolating theepoxidized fatty acid esters.

References Cited in the file of this patent UNITED STATES PATENTS2,377,038 Reichert May 29, 1945 2,485,160 Niederhauser Oct. 18, 19492,801,253 Greenspan July 30, 1957 2,810,732 Greenspan Oct. 22, 19572,813,896 Krimm Nov. 19, 1957 2,873,283 Yang Feb. 10, 1959 2,976,265Pearce Mar. 21, 1961 2,997,484 Beavers et *al. Aug. 22, 1961 OTHERREFERENCES Gall et al.: The Journal of the American Oil Chemists Soc.,vol. XXXIV, No. 4, pp. 161-164, April 1957.

